1. Field of the Invention
The present invention relates to a cap of a distributor for use in an electric ignition device for an internal combustion engine. More particularly the present invention pertains to an improvement in the connection of the distributor cap and an ignition cable.
2. Description of the Prior Art
FIG. 1 shows a typical conventional distributor cap of the type described above. Referring to the figure, the reference numeral 1 denotes a distributor cap body made of a synthetic resin material. The cap body 1 has a central projection 1a and a plurality of side projections 1b, which are formed on the upper side thereof so as to project upward as viewed in the figure. The reference numeral 2 denotes a central terminal which is buried in the central projection 1a. The central terminal 2 has a contact member 4 vertically movably supported within the lower portion thereof through a compression spring 3 which biases the contact member 4 downward. The reference numeral 5 denotes a side terminal which is buried in each side projection 1b. A distributing member 6 which is shown by the two-dot chain line is fitted to a rotor 7. The distributing member 6 has a distributing conductor strip 8 buried in the upper surface thereof. The conductor strip 8 is in resilient contact with the contact member 4. Thus, as the distributing member 6, together with the rotor 7, rotates, the distal end of the conductor strip 8 comes to close proximity to the side terminals 5 to apply a high voltage thereto sequentially.
The reference numeral 9 denotes a central ignition cable which is connected to the secondary winding (not shown) of an ignition coil, 10 is a side ignition cable connected to each ignition plug (not shown), 11 is a plug-in terminal which is press fitted on the terminating end of the ignition cable 9 to connect with the core wire 9a and which is plugged in and thereby brought into contact with the central terminal 2, and 12 is a plug-in terminal which is press-fitted on each ignition cable 10 to connect with the core wire 10a and which is plugged in and thereby brought into contact with the side terminal 5. The reference numeral 13 denotes an elastic cover which is made of a rubber-like elastic insulating material, the elastic cover 13 being fitted on each of the ignition cables 9 and 10 and having the inner peripheral portion of its distal end fitted on each of the projections 1a and 1b, thus serving as insulating and waterproofing means.
The above described conventional distributor cap suffers, however, from the following problems. Namely, there is a fear of contact failure occurring between the plug-in terminals 11 and 12 on the one hand and the central and side terminals 2 and 5 on the other due to vibrations or insufficient plugging. In addition, the elastic retaining capability of the elastic covers 13 may be deteriorated due to overheat, corona discharge or the effect of water, oil or the like to such an extent that the ignition cables 9 and 10 cannot be sufficiently retained, which leads to various problems, for example, electrical contact failure, waterproofness failure and disengagement of the ignition cables 9, 10.